Drove the GR86 today after fitting the Nameless V-braces, both around town and on the motorway.
I can't really quantify the improvement properly, but there is definitely a noticeable difference.
The steering/front-end feel feels around 5% better to me — slightly tighter and more direct.
The biggest difference is the noise/resonance, which I'd say is around 20% better. The car just feels a bit quieter and less harsh, particularly at motorway speeds.
Obviously these aren't scientific measurements, just my personal impressions, but after driving the car in different conditions today, I'd definitely say it's an improvement and I'm happy with the result.